Photographic ray-filter.



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No. 886,684. PATENTED MAY 5, 1908. P. J. DUKBLOW. PHOTOGRAPHIG RAY FILTER.

APPLICATION IILLD JAX 20 1908 /ELQ/e-f ing and provide at UNITE sTATEs PATENT onirica.

PETER i. DUKELOW, or BUFFALO, NEW Yonicfassienoa ro SPENCER LENs'cOMrANY, OE

BUFFALO, NEW YORK. l

PHOTOGRAPHI RAY-FILTER.

Application led January 2A0, 1908. Serial No. 411,670.

To all wiomjt may concern:

Be it known that I, PETER J. DUKELow, a citizen of the United States, residing at Buffalo, in the county of Erie and State of New York, have invented a new and useful Improweinent in Photographic Ray-Filters, of which the following is a specification.

This invention relates to improvements in photographic ray filters of that type in which a suitable solution or fluid in a transparent container isemployed for filteringl the rays4 of light which pass to the photo` graphic negative. Filters of this character have been made. in which the container or receptacle for the filtering fluid consists of two glass )lates spaced apart and held )arallel with each other by an. interposed at-sided'ring or short cylinder.

Owing to the nature of' the filtering fluid generally employed, it is desirable to forni the container entirelyr of glass and for this purpose a glass spacing ring or cylinder is employed which is preferably of the .saine iainetei` as the glass plates. As dill'eient filtering fluids are einiloyed for different effects and the strength and nature of the various fluids are also changed in accordance with the character of the results required, it is necessaryT to either employ a number of difl'erent filters, which is expensive, or else change the fluid in the container as may be required, and in doing this,the container inust be emptied and thoroughly washed before being refilled.. In refillin the filter, air bubbles are frequently forme( which gather on the inner surfaces of the glass ilatcs and the spacing ring, and these bubbles, unless removed, interfere with the passage of light through the filter.

iThe ob'ects of this invention are to construct a filter of this character which may be easily emptied, washed and refilled, and to i'ovide the container with a suit-able stopper or the filling opening in Vthe saine, which, when in place, will tightly close such Open face of the spacing ring, a pocket for rccciv ing the air bubbles which may have formed in the filter, and holding them outside of the fi'eld of' the filteiwliere they will not inter ferc with the passa-gc of' light through the same.

In the accompanying drawings: VFigure 1 is a perspective View of the container of a Specification of Letters Patent. p

4parallel sides, and

the. top of' the container above the highest portion of the inner 'sur- Patented May 5, 1908.

photographic ray filter embodying the inven- Y tion, the parts being separated to .more clearly show the saine. Fig. 2 is a transverse sectional elevation of the filter `and its holder, taken in line 2t-2, Fig. 4. Fig/3 is a front elevation thereof. Fig. 4 is a vertical section thereof, showing the saine in position upon the lens tube of a camera.

Like letters of reference refer to like parts in the several figures.. A represent the two circular side plates, and B filter'container. This ring 1s of uniform width throughout, having opposite flat and the flat surfaces of the ring and of the side plates are so ground that when the plates are iiivposition against the opposite sides of optically parallel with each other so as not to passing through the filter.

The -ring B is provided with a filling and discharging ripening b which extends entire] through the ring from side to side thercoi, and is of sufficient size to allow the container to be readily emptied and refilled. 'A stopper C of the saine width as the ring B and of segmental cylindrical forni, is ada )ted to close this opening, the end walls ofl which are concaved to fit the cylindrical surface of the stopper. The contacting surfaces of the stopper and end walls of the opening are ground so that the stopper fits closely in the opening or seat in the ring B and forms 4a tight c Osure for the same. 0n its inner or underside, the sto per is provided with a cavity extending fibni end to end thereof, which, when the stopper is in position upon its seat in the ring B, foi-nis a pocket c located outwardly be foi'idthe inner circumference of this ring, an(

terfering with the ypassage of the rays of light through the ltei. of thestppper is concaved on the saine curvature""a's the inner surface or ieriphei'y of the ring B and the stop )er can Ibe turned in its seat to place this under-concaved surface ex- 'actlv flush with the inner surface of the ring, sce iig. il, whereby the stopper will not project into the filter chamber and form an obstruction which would ti'ap the air bubbles and prevent them from flowing freely into the receiving pocket c.`

the .spacing ring or cylinder of the' this ring, they will be' adapted to receive and retain therein any air bubbles which may form ine the filter and thus prevent the same from 1n- The inner or underside ses The contacting surfaces. of the various parts of the filter are so ground that when" they are placed together, closely fitting and Any-suitable frame or holder is provided for securing the parts of the filter together and attaching the same to the camera. In the construction shown, this holder-consists of a tube or ring D of substantially the same Widtlras the filter container and adapted to Wardly-extendin A which embrace the outer edges'of the plates l im .surround the saine. This tube or ring is pro vided on its front and rear'sifdes With infr retaining flanges d and d A of the container. These flanges are se-` cured to the tube ring D by screws, or in any other desirable mannerperi-nittinfr them to be drawn up tightly against the plates A of4 the container to clamp the plates against the spacing ring B. The rear fla-nge d is rovided with a tubular extension 'd2 whici is .adapted to telescope With the lens tube E of a camera to hold the filter in position thereon. The holder tube or ring D is provided with, av suitable hole or opening d3 opposite the filli'ig and discharging opening of the filter, through which the stopper can be i'eadily inserted into and removed from the filling and discharging opening. Thi` `stopper C is held firmly in place on its seat in the container by a suitable latch, Aspring strip F is prefen .ably employed which is hinged at one end to the holder tube or ring D at one side of theopening d with its free end ada ted to detachably engage under a hee erpivoted to the holder tube' or ring ,Dat t ieop posit-e side of the opening. -A groove f is )rovided on the outer side ofv the Stopper C which forms a f seat for this spring latch. Any other suitable' means,howevencould be employed for securing the stopper in position in "the filter. 1l/Vhen it is desired to change the filtering fluid, the latch F is released and the stopper C removed and the contents poured from lthe container. The interior of the container is then Washed by ournig therein some suit- -'able washing flui and when this is done, the

container is filled with the nenr filtering fluid to be used and the stopper inserted and se- 4 lcured in placetherein., r'lhe lair bubbles which may gather on the interior surfaces of `tli'e filter -can be caused to rise into the pocket rc on the under sideof the stopper by gently jarring and turning the filter. The size of the opening in the ring B of the filter permits the rapid filling and emptyinr thus enables the contents of the filter to be quickly changed. i

I claim as my invention:

thereof and' 1. In a photographic ray filter, the eombii 'nation of front and rear transparent plates, a spacing ring between. said plates forinin t erewith a container for the filtering fluid and having a filling opening therethrough which extends from lside to side of said ring, and a stopper'for 'Closing said opening, substantially as set forth. f i 2. In a ihotographic ray filter, the combination offrent and rear transparent plates, a spacing ring between said plates formin t ierewith a container for the filtering fiuif and having a filling openin therethrough which extends from side to side of said ring and has concaved Walls, and a stopper having a cjdindrical outer surface adapted ,to fit said concaved end walls and close said opening, substantially as set forth. f'

3. Ina )hotograpliic ray filter,- the 'combi-i nation of front and rear transparent plates, a 's iacing ring between said lates forming therewith a container for the ltering fluid, a filling opening in said ring, and a stopper for closing said opening provided on its inner side with a cavity forming an 'iii' pocket extending-outwardly beyond the inner circumference of said ring, substantially as set forth.

4. In a photographic ray filter, the combination of front and rear transparent plates, a

s acingring between said )lates forming t erewith a container for theA ltering fluid, a filling opening iii said ring, and a'stopper for closing said openinv` provided with a'concaved' inner face fiuslli with the inner periphery of said ring and having alcavity therein forminvl an air pocket extending outwardly 'beyond7 said inner periphery, substantially asset forth, f i

Witness my hand, this 10th day of Jann ary, 1908.

INitnesses:

C. W. PARKER,

. C. B. HonNnncic. 

